1. Field of the Invention
The present invention relates to a metal-air battery system including a CO2 selective absorber and to an operating method therefor.
2. Description of the Related Art
Metal-air batteries have been attracting attention as next-generation large capacity batteries to replace Li-ion batteries. However, metal-air batteries are problematic in that the cathode becomes clogged by a low-solubility compound generated by CO2 contained in air during a discharge reaction. JP H05-062687A, JP H07-105991A or JP H07-014565A describes an oxygen permselective cathode that uses a membrane of a polymer such as fluororesin or polydimethylsiloxane to remove CO2 contained in air, but it is difficult to sufficiently lower the CO2 concentration with an oxygen permselective cathode that uses a polymer membrane.
JP 2002-516474A reports an air battery that has an oxygen concentrator. This air battery uses zeolite for oxygen concentration and not for CO2 absorption. Moreover, although there is a description of a CO2 absorber, because no recycling mechanism is provided, CO2 reaches saturation and the adsorption member deteriorates, resulting in a problem in that only a certain amount of CO2 can be absorbed.
Also, JP H11-253736A reports zeolite as a CO2 absorber for process gas. However, due to the small Si/Al ratio, this zeolite is hydrophilic and preferentially adsorbs water vapor when used in air, and thus the CO2 adsorption performance is insufficient.